Liquid fuel injection means for internal-combustion engines



Patented Apr. 11, 1950 LIQUID FUEL INJECTION MEANS FORINTERNAL-COMBUSTION ENGINES Maurice Carey Wilks, Solihull, England,assignmlan to Rover Company Limited, Solihull, Eng- Application May 9,1947, Serial No. 747,089 In Great Britain August 21, 1944 1 Claim. (Cl.299-1071) This invention relates to liquid fuel injection means of thekind comprising a nozzle or nozzles through which measured quantities ofpetrol or other like liquid fuel are injected by a Pump into theinduction pipe or cylinder or cylinders of an internal combustionengine. Ordinarily the orifice of the nozzle is controlled by aspring-loaded closure member, and both the closure member and itsseating are made from metal. Difficulty has been found in ensuringproper closing of the said member on its seating owing to the depositingof minute solid particles thereon or on the seating from the liquid orother source. A result of this condition is that when the engine isrunning with the throttle valve closed or nearly closed, the

partial vacuum in the induction pipe, (or in the cylinder or cylinders)causes undesired fuel flow through the improperly closed nozzle ornozzles, with consequent defective running of the engine and wastage offuel, especially at idling speeds.

The object of the present invention is to enable the undesirablecondition above mentioned to be avoided in a convenient and satisfactorymanner. 7 The invention comprises the combination with the liquid fueldelivery nozzle, or each such nomle,

- of an air or other gas chamber situated around and enclosing thenozzle outlet, and having a constantly open discharge orifice ororifices spaced from and in advance of the nozzle outlet, and meansformaintaining at all times in the said chamber an air or other gaspressure which is independent of the air required for combustion of thefuel delivered by the nozzle, and which is sufficiently in excess of theengine intake pressure to prevent fuel from being drawn through thenozzle outlet.

"The accompanying drawing is a sectional side elevation of liquid fuelinjecting means embodying the invention.

In the drawing it indicates a nozzle, or one of a plurality of nozzles,through which measured quantities of petrol or other like liquid fuelcan be injected by a pump into the induction pipe or cylinder of aninternal combustion engine. The nozzle a is provided at its front endwith a liquid fueldischarge orifice b, and contains a springloadedclosure member past which the liquid fuel to flow to the dischargeorifice. In carrying the invention into effect as shown, the nozzle a isenclosed by; a sleeve d forming an air or other gas chamber around andat the front end of the nozzle, the sleeve being formed at its front endwith a constantly open discharge orifice or orifices as e. The interiorof the sleeve d is kept at all times filled with air or other gas (whichmay be engine exhaust gas) at a pressure which is independent of the airrequired for combustion of the 2 fuel delivered by the nozzle a, andwhich is sufllciently in excess of the lowest pressure which may existin the engine induction pipe or cylinder (as when the throttle valve isfully closed) to prevent the extraction of liquid fuel through the fuelnozzle by suction, in the event of the nozzle closure member c beingimperfectly closed. The desired preponderance of pressure in theinterior of the sleeve d may be obtained by suitably dimensioning itsvolume and/or its discharge orifice or orifices as e, in which case therear end of the sleeve may be in free communication with the outeratmosphere. When engine exhaust gas is supplied to the interior of thesleeve d, the pressure of this gas may be sufilcient to serve thedesired purpose. But it may be preferable to employ a small air or othergas compressor or blower adapted to maintain the desired pressure in thesleeve d. In any case the rear end of the sleeve :1 may be accured to ahollow fitting I having a laterally arranged inlet Opening a for the airor other gas. It will be understood, however, that the amount of air orother gas which can pass from the interior of the sleeve d to theinduction pipe or cylinder is not sufilcient materially to affect thenormal action of the engine.

The invention is not, however, limited to the example described as theform of the nozzle and sleeve may be varied to suit requirements.

Having thus described my invention what I claim as new and desire tosecure by Letters Patent is:

Liquid fuel injection means for an internal combustion engine,comprising the combination with a liquid fuel delivery nozzle having anoutlet at one end, of a gas chamber situated around and enclosing thenozzle outlet, and having at least one constantly open discharge orificespaced from and at the outer side of the nozzle outlet, and means formaintaining at all times in the said chamber a gas pressure which isindependent of the air required for combustion of the fuel delivered bythe nozzle, and which is sufficiently in excess of the engine intakepressure to prevent fuel from being drawn through the nozzle outlet.

MAURICE CAREY WILKS.

REFERENCES CITEP The following references are of record in the file ofthis patent:

( FOREIGN PATENTS Number Country Date 7,219 Great Britain 1899 7,702Great Britain 1915 29,879 Great Britain 1910

